WASHINGTON (CNN) - A new national poll indicates that Americans think President Barack Obama's performance on the economy deserves a grade of C.

The CNN/Opinion Research Corporation survey, released Thursday as the president approaches 200 days in the White House, asked respondents to use a grading scale of A, B, C, D, and F, where A is excellent and F is very poor.

Fourteen percent of those questioned gave Obama an A, 24 percent a B, 25 percent a C, 13 percent a D and 23 percent an F. The president's grade on the economy averaged out to a C.

The president also received a grade of C on the economy in a CNN poll taken as he approached 100 days in office.

The CNN/Opinion Research Corporation poll was conducted July 31-August 3, with 1,136 adult Americans questioned by telephone. The survey's sampling error is plus or minus 3 percentage points.